Drag Conveyor Chain Link Set

Function

The drag chain's primary function is to pull slat flights or scraper bars along the conveyor trough at a controlled speed, transporting a defined mass of hot aggregate per unit time from drum discharge to mixing unit without segregation or excessive temperature loss. Chain link wear manifests primarily as pin-and-bush elongation that increases effective pitch, causing the chain to ride up sprocket teeth and accelerating tooth wear. A worn chain also generates vibration that stresses scraper flights and conveyor frame welds. Replacing the full chain set before pitch elongation exceeds 2 % avoids the compounded cost of sprocket replacement and frame weld repairs.

Construction & quality

Side links: drop-forged alloy steel (40Cr carbon-manganese grade), quenched and tempered to 340–380 HBW. Pins: case-hardened alloy steel with surface hardness 58–62 HRC to a case depth of 1.0–1.5 mm and a tough core at 35–40 HRC. Bushes: oil-impregnated sintered bronze (lubricated designs) or through-hardened steel (maintenance-free designs) as specified. Assembled pitch tolerance: ±0.15 mm per link across the full set. Sets are pre-assembled in matched batches and proof-loaded to 1.5× rated working load before dispatch, with a certificate per set. Retaining clips: ISO 606 split cotter pins or spring clips matched to the original conveyor design.

When to replace

• Measured chain pitch elongation exceeding 2 % of nominal, checked with a calibrated pitch gauge.
• Audible chattering or periodic vibration during conveyor operation, indicating chain-sprocket mis-engagement.
• Visible side-plate cracking, particularly at pin holes in links that have experienced shock loading.
• Accelerated sprocket tooth wear or tooth hooking — often caused by an elongated chain rather than sprocket fault.
• Slat flight mis-alignment or recurring conveyor jam events during normal operation.